pascalsTriangle.js

// Given numRows, generate the first numRows of Pascal's triangle.
// For example, given numRows = 5,

var generate = function(numRows) {
  var pascalsTriangle = [ [1] ];
    
  for (var i = 0; i < numRows - 1; i++) {
    var row = [1];
    for (var j = 1; j < pascalsTriangle[i].length; j++) {
      row[j] = pascalsTriangle[i][j] + pascalsTriangle[i][j-1];
    }
    row.push(1);
    pascalsTriangle.push(row);
  }

  return pascalsTriangle;  
};